Knife sharpener



FIG. 1 is a perspective view of a knife sharpener, embodying the new design;

FIG. 2 is a front elevation view of the knife sharpener of FIG. 1 ;

FIG. 3 is a rear elevation view of the knife sharpener of FIG. 1 ;

FIG. 4 is a top plan view of the knife sharpener of FIG. 1 ;

FIG. 5 is a bottom plan view of the knife sharpener of FIG. 1 ;

FIG. 6 is a left end elevation view of the knife sharpener of FIG. 1 ; and,

FIG. 7 is a right end elevation view of the knife sharpener of FIG. 1 .

The broken lines illustrate portions of the knife sharpener in which the design is embodied that form no part of claimed design. 

CLAIM The ornamental design for a knife sharpener, as shown and described. 